This CUA Guideline was initially developed in 2008. The recommendations were based on a literature review which was carried out in 2007 to determine whether perceived medical concerns regarding MCDK could be substantiated, and to determine what degree of urological investigation and observation was actually necessary for the neonate with a MCDK. The findings of this literature search are detailed in the article: Psooy K. Long-term follow-up of MCDKs: Is it still indicated in 2007: Can Urol Assoc J 2007;1(2):113. (http://journals.sfu.ca/cuaj/index.php/journal/article/view/53/50). In 2015, this CUA Guideline was updated following a 2014 literature review to determine whether management controversies continued to exist, to obtain up to date information regarding the medical implications of having a MCDK, and to determine the appropriate investigation and follow up for same.